Arthur



A. E. PAI GE. MULTiFOCAL OPTICAL ELEMENT AND METHOD AND MEANS FOR MAKING THE SAME.

AIFLlCATlON F'ILED NOV. 4,1920..

qieissuei Dec. 14, 1929.

' 'INVENTOR: 60A

nr OFFICE.

' 'LVIUIRIIIEOGAED OPTICAL ELEMENT AND METHOFB AND MEAHS FOR MAKING THE SAME.

Specification of Reissued Letters Patent. fieissued Dec, 14 192(} Briginal Ne. 1,351,?!35, dated Sepiemher 7, 132%, Serial I070. 882,525, filed fletober 22, 1919.

Application for reissue filer; November 4, 1920 Serial No. 422,104. I

To all whom it may cone-29 21 lie it known that l, Aer-non E. PAIGE; a citizen. of she United l lelphia, in she e uuty o'l' lhilsdel l ihiu and St t-e o" Pennsylvania, have invent-ed a certain new. and u n] line ovemcnt in lllul'tifocal Uplcieal nnenls and Iliiethods and llleans for liiehing the Same, whereof lhe following is e spool cation;reference beinghad be the ncconipn. L ng drawings.

lily invention relates to optic-cl elements of ilhe generel char cter contemplated in *"Prs l'Petent of lhe Unified States No. 555 granted lo meduly 1918, ll!) wit, T its which have an optical surface includig both spherical said a non sphei id area which one ll/ ouch. other wi-xont linear demercati y invention is particularly applicable in; ophthalmic lenses 1 med of a single piece .iss of uniform index of refraction and dc; good to uilord dii'lerent courec iion for v' ion at different d tune-es. @rdinarily, such lenses merely s ifocnl, includinge nmjor area, of uniform focus, adapted for distunl vision, end a minor ares of differout bui uniform locus, adapted for near v':ion; said, areas, iunnediately adjoining each other and having :1; distinct line of G division between them; said line being muniiesled either by an offset by the. abrupt terminmfiion oi the respective incl areas indifferentv pl f, or by a. ridge U the junction oi said su es in a plane 5 muimon to bol-h there. till such. lenses the prior art produce aberration of vision through the region. of the unciiion of their rmpcci'ivcly different focal areas, and thc object of subsrmrliully all pulenicd ll'llell uroveuients in such lenses has been the forinnrion ihe diinercnsly'curved surfaces with a sharply defined jui ltion line lielwecn lihcm; if, being assumml hurl; such elm-111 lion. would be minimized in co: rcspoi'uleuce ii the sharpness of such junction lines. oweveiu such aberration is duev to the ion inuiiion of double, relatively displaced, inmues of every object seen eh'rou rh the linciir junctions of said differemt local areas due to the abrupt juxljupo. ion of thocdgos thereof in such :11 ,yulur relation as to prod! u prismatic c ..oct, and the formation 1h double iumg; s is neither prevented l b the shsu'penin oi the on lines which has been he object cs, residing all ledge, donned of the prior art. Such aberration is particularly objectionable in vision which is downcasi "to the degree necessary to descend stairs, because such aberration is then mzxnifes'led by double vision of the successive steps making it impossible for the wearer of such lenses to precisely determine the location of the edges of the step treads; and the danger of such lenses under such oircumstences is recognized in text books relating tothe art of fitting such lenses which instruc t that purchasers of such lenses should be cautioned to avoid dependence upon vision through them under such circumsitenes.

1t an object of my invention to avoid the objections aforesaid with reference to ordinary lenses intended for bifocal vision,- by providing lenses with a multifocal surface which is smoothly continuous from the top "to the bottom thereof although of differ ent dioptric curvature in different regions, so that the upper portion afiords the proper correction for distant vision and the lower portion affords the proper correction for vision and the'region between the two .iziremes is of an intermediate curvature; the zidvenl'age of such construction and illrzlngeinenl being that vision through any portion of said surface affords a single continuous visual image, instead of the double, relatively displaced, images which are charaotorisiic oi. the bifocal lenses of the prior erh i However, as hereinafter described, an. ophial'inlinic lens may be formed in accordance with my invention including two areas of re speczively i'lillerent dioptric power, merged into each oth r wiizhout any line of demarcation, 'nnd flout any intermediate region which is dissinct in dioptric power from either oi slid areas, one of said areas forminn" what is known as a truly sphcriccl' lei and the ()t-llfl'lfi sail l7, wliui'. ure harmed cylindrical componcntsor elements in. transverse relation or forming what is i'ei'rncd :1 fcross cylinder, which is equii 'ulent to a truly spherical lens. In such a bifocal lens; the two areas have a common curvature all their junctions, upon both sides of the glass. although the junction curvature areas including may he (ii 'l crcul' upon the opposite sides oi oi she glass, the so called xvc vliudrin'zul clcments of said toric surfaces having their axes at right angles to each other. A truly cylindrical surface is straight in any plane radial to the axis of generation of the cylinder and, in the optical trade, the portion of I such a surface which is thus straight is termed the cylindrical axis and cylindri cal element of such surface and, adapting that nomenclature to toric surfaces, the portion of such a surface which is most nearly straight i. e., the portion having the curvature of greatest radius, is termed the cyliudrical axis and cylindrical element of such toric surface, and it is suchcylindrical elements of toric surfaces which have their axes at right angles to each other as above contemplated, and thus form a cross cylinder, which is equivalent to a truly spherical lens.

Regardless of whether thereis or is not such-intermediate zone of distinct dioptric power, and regardless of Whether either of arc in a plane at right angles to the axis of generation of such surface and concentric,

with that axis, and also conform to circular arcs concentric to that axis in every plane parallel with that junctiona-l plane. However, the curvature of regions of such surface extending from such junctiomin either direction, may be of any desired optical character in any plane radial to said axis of generation. Of course, if the latter"curvature is circular and of the same radius as the junctional curvature, then the, surface coincidingtherewith is spherical. If the curvature in such plane radial to t e axis of generation is of'less radius than .he junctional curvature, then the surface coinciding therewith has a cylindrical-compdnent with its axis parallel with said junctioual curvature and if the curvature in such radial plane is of greater radius than'said unct1onal curvature, then the surface coinciding therewith. has acylindrical component with its axis in a plane at rlght angles to the plane of said junctional curvature, and, of course, in a plane radial to said axis of generation. Of

course,-if such radius is infinite. and the surface consequently straight in such radial plane. such surface is truly cylindrical. Any visual image seen through an optical surface having a cylindrical component appears either magnified or minified transversely to the cylindrical axis of such surface, accord 'rninus) or of opposite sign.

.into each other,

7 vent ion.

' at the horizontal diam say, the refractive effect may be rendered in uniform in every direction. by embodying twocylindrical elements in the same area of a lens, either in crossed relation, or with their axes 1n the same plane, depending .upen

Whether they are of the same sign (plus or 7'5 So that, in

accordance with this invention, optical ele merits may be produced with any desired optical power upon opposite sides of-such.

juncticnal region of common curvature.

As hereinafter described, such'multifocal optical elements may be surfaced by means of laps having corresponding surfaces, by

relative oscillation of the glass and lap in.

the direction of the junctional common an vature above described. That is to say {the surface thus produced is a surface of reve lut1on, the axis of generation of which extends through a center of said common curvatu each entire surface of suchja lens 9 being curved with reference to a single axis of generation of that surface but with zones of different dioptric powers at diiicrent dis-.

tances-from said axis; said zones merging generically claimed in said Letters Patent. I f My invention includes the various novel features of construction, arrangement and procedure hereinafter more definitely speci fied."' ln'said drawings Figure I is an elevation. of the inner face of a multi focal ophthalmic lens embodying-my invention and adapted for correction of presbyopic vision. Fig. II is vertical sectional-viewof said lens taken: on theline 11,". H in Fig. I; Fig. III is an elevation of the inner face of ajmultifocal ophthalmic lens embodying my invention and adapted for correction of myopic vision. Pig. IV is. a vertical sectional view ,pf' said lens, taken on the'line IV, H in l ixl'll, Fig. V is a plan View of n ultifccal lap em hodyingmy-invention, which may l e-em ployed to surface the inner-face of the lens tional view VI, VI in Fig. V; Fig. 'Vll'is an inverted plan view of said lap. Fig. VIII is a verti;-

cal sectional View of a modified form of lap embodying my invention, which may be employed to surface the outer face of thelens shown in Fig; ll. Fig. TX is an elevation of n uiultifccal'clemcntembodying .my inwith an intermediate transition zone. v

, li cirrriug 1 has throughoi-lt its semicircular area 3,

above its geon'ictrival center, a spherical sur- 7 face of '6 dioptcrs cur ature, terminating tier of the glass dish to Figs. 1 and llz'the glass-disk thy an c or s the 180 degree in aid r. isli s, throughout its semiarea 5. lJuiOlY said line l, a tone suricu is of +6 diopters curvature horiv, so as to merge into said spherical at the tn'icter i, but has a curvaas at right angles to said lat opticians term its 90 a are dotted. line 6 in Fig. 1 id inner toric surface its cylindrical element or ically. Said disk 1 has, indicated in F H, and

4, spherical surface of +7 ire and said disk 1. has, upon ,roughout the semicircular .id line l, a toric surface which of +7" diopters horizontally,

d upper spherical surht angles thereto, and till axis aforesaid, a curvature of +9 That to say; said outer toric the disk 1 hasits cylindrical eletcnaling horizontally. Conyer semicircular area. of herical lens of +1 dioptric nears, the semicircular area l a cross cylinder affording ating power o much greater than that in upper semi rcular area 3 that said are :5 may be used for distant vision, -ie lo rcr area for reading, a person in. The addition of the Ate re i'iractive power subant to that ofa spherical di-.;.=ters; but, of course, differ- "our such a. spherical lens in that the disposed cyliudric; y; the difcc bet'vvecn the concave aid convex surface curvatures in the 90 degree plane of section of a d. area shown in II, and all planes parallel to that plane, being +4 diop'lers, Wllfil'fitlfl, the diillercnce between the ncavr and (.UIW'P" surface curvatures in the 184,) d :a plane of said disk 1, and all idol to that )ltLDQ, throughout being but +1 tiopter so that any p" imprint, is inr-ignilied vertically o ts width. Such cylindrical due to the fact that said 2d ryliiul ical components are oi oppoone plus and the other minus, h the meniscus shape of 1 in which. they are embodied. If

. as in. a :muille convex lens, Where wins or in a double concave lens,

e r ms; the respective rer-r ml cylindrical with substantially idllllfillcllltll' area above said' :nnponents in said area 5 pro-- l through said area 5, for in-- ionen'ls were both of the the same refractive effect in both the 90 degree and 180 degree axes of the lens in equivalency to a truly spherical lens, as above contemplated. Moreover, the refractive eifect of a cylindrical component of either sign, (plus or minus) is equivalent to the refractive effect ofa cylindrical component of the opposite sign, if its axis is at right angles thereto. For instance, the minus cylindrical component having its axis at 90 degrees in Figs. I and II is the refractive equivalent of the plus cylindrical com ponent having its axis. at 180 degrees in said figures. So that such cylindrical components may be readily transposed, to Whichever sign and axis may be most conveniently embodied in the form of lens to be made. and

such substantially uniform refractive effect as is characteristic of a. truly spherical lens may be produced by embodying cylindrical components of opposite sign upon opposite surfaces of the lens provided that their axes are in the same plane, for instance, both at 90 degrees as isthe minus cylindrical component in the disk 1, or both at 180 degrees as %s the plus cylindrical component in that dis Referring to III and IV; the glass disk 8 has, throughout its upper semicircular area '10, a spherical surface of 6 diopters, terminating at its 180 degree axis, to Wit, the horizontal diameter of the glass in dicated by the dotted line 11. Said disk 8 has. throughout its semicircular area 12, be-

V low said line 11, a toric surface which is -6 diopters curvature horizontally, so as to merge into said spherical surface, at the dialneter 11, but has a curvature of 4 "diopters at its 90 axis, indicated by the-dotted line 14-, at right angles to said line 11. That is to say said inner toric surface of the disk 8 has its cylindrical element or axis extending vertically. Said disk 8 has, upon its outer face indicated in Fig." IV, and throughout the semicircular area above said diametrical line 11, a spherical surface of +3.25 diopters curvature, and said disk'S has, upon its outer face, throughout the semicircular area below said line 11, a toric surface which has a curvature-of r "p-' ters horizontally, so as to merge into said uppers )herical surface, but has, at right angles thereto, to wit, at its 90 axis aforesaid, a. curvature of +5.25 diopters. That is to say; said outer toric surface of the disk 8 has its cylindrical element or axis efitcnding horizontally. Consequently, the upper semicircular area of said disk 8 is a spherical lens of +2.75 dioptric power, whereas, the lower semicirciular area of said disk 8 is a cross cylinder aytfording retracting pou ey so much less than hat of the upper semicircular area 10, that i'aid upper area maybe used for distant vision and the lower area'12 for reading, by a person with myopic vision.

. ,ter surface upon 'the As before noted; the lens shown in Figs.

I and II is adapted for correction of presbe used as a lap, must have its working face in such 0 posite relation to the surface to be generate or polished, as to impose the latlass or other material of which it is being ormed.

The lap shown in Figs. V to VII inclusive is conveniently formed of two iron castings, 15 and 16, the former having a spherically curved surface 17 and the latter a torically curved surface .18; said differently curved surfaces having a common curvature at the junction line 19, which is the line of division between said castings. Said-castings have complementary lugs 21 and 22 which form an oblong boss of standard shape and dimensions designed to fit in commercial adapters for connection with rotary spindles of commercial surfacing mechanisms. I find it convenient to rigidly couple the lap sections 15 and 16 by the screws 23 and 24, respectively engaged in the threaded holes 25 and 26 in said lugs 21 and 22, and respectively extending through the smooth holes 27 and 28 in said, lugs; said smooth holes being large enough to permit relative adj ustment of said sections to prevent a smoothly continuousworking face. y

I find it convenient to employ laps of the sectional form, above described, to minimize the number of tools requared to meet the trade requirements for bifocal lenses; as such toric lap sections, of idiifere'nt proportions, may be interchangeably connected with a single spherical ,lap section, provided, of course, that they; have a common curvature at their junction. However, laps havin such multifocal surfaces as above descri ed may be formed of a single piece of metal, or other material; such multifocal surfaces as described being readily formed -b the commercial radius cutters and radius grinders ordinarily; employed for forming toricsurfaces upon laps. Fig. VIII illustrates such a one piece multifocal lap 29 having "its working face concavely curved; the semicircular area 30 thereof being spher- 'ically curved in opposite correspondence with the upper outersurface of said disk. 1, and the semicircular surface 31 of said lap 29 being curved in conformity with the lower outer toric surface of said disk 1 said two surfaces 30' and 31 having ajcommon curvatu'reat the plane indicated by the effect of any such lenses upon of greater or less refractive posite spherical. surfaces crossed cylindrical elements oftcric faces, immediately joining each other out even a linear demarcation between or anything to interrupt the smooth continuity of the curvature of the sur "aces of t lens upon either side of the in g forming it. However, it is to be uncle that, as indicated in IX, a mulei c element embodying my present and, including areas of different d curvature respectively formed by a sp. cal surface 34: and by a toric surface Ina include an intermediate zone 3% of an h P vature as to afford a gradual. trans a. dioptric power from said spherical. sui r. to said toric surface, as contemplated in Letters Patent aforesaid. For such a zone may be bounded upon edge by the horizontal diameter as oi: lens (its degree axis) and be lJ-Sm upon its lower by a pl with said axis, say four or hr distant therefrom; the curvature of the face of said element at the latter plane l. common to the areas respectively extenoir above and below the same. Of course, as such a plane, of junction as above contemplated is'not a diametrical plane with reference to the spherical sui ace extending above it, itaffords a junction of less radius of curvature than a diametrical junction and is correspondingly stronger in dicptfic power in accordance with its distance fr! such diameter. Although the lense which for illustration havc'both which are respectively inner lib l focal character; I do not as self to such embodiments c y for it is obvious that a lens may be with but one of its opposite suri'ac multifocal character and the other of u form dioptric power, plane, spherica vex or concave, or cylindrically convex L concave. Of course, the optical "lower o such lenses as above described, is

mined by the shape of their mass and tive position of their surfaces, their location in race; but, ophthalmic purposes, their to the eyes of the user is im liiil the wearer depends upon power is above or below its 3.80 degree axis. instance,

liner in the lens 1, shown in Fig. H, the area of greater power is below such but-in the lens 8, shown in Fig. IV, the area of greater power is above. However, Wl'iether the upper or the lower area shall include a cylindrical element or crossed cylindrical elements, such as described. is merely a reatter of convenience.

Moreover, although i have illustrated my invention as embodied in opl'ithaliuic lenses; it is to be understood that it may beiembodied in lenses adapted for other purposes and in other op 'al element's, Whether refractors, or reflectors or refracting' reflectors. F or instance; any of the elements illustrated may he provided with an opaque surface to form areiracting mirror, or a substantially total reflei'rtine" mirror, or, an opaque element (such as the laps afore said) may be provided with a surface curved in accordance With my invention to form a substantially total reflector. Such reflectors may, for instance, be placed. behind the source oflight in avehicle lamp, to dis tribute the light both distall and locally, laterally, immediately in 'i'ront of the vehicle.

Oi. "course, such construction and arrangement as above described connotethat, in each instance, the axis of generation of the inultifocal surface is an axis of symmetry with reference to which the different areas of such surface are disposed and is the locus of the centers of the spherical. curves contemplated. In other Words; the inulticurved surface of each of the optical elements alnrve described, including both lenses and laps, is generated by movement of a compound curvewith reference to a circular directrii: and an axis of generation concertric with the directrix.

For instance, in Fig. Ill the axis of n eration of the convex surface of the disk 1 is indicated at 41, and the axis of genes ation of the concave surface of said dislr is indicated at 42, and, in each case, the directrix' coincides with the zone of common curvatiu'e of the different areas of" the respective surface. Although I have shown said axes 41 and 4:2 in parallel relation; they may berelatively inclined to equalize the thickness of the opposite edges of said disk. Moreover, although I have indicated the principal focal axis of said dish, normal to its geometrical center, the locus of all of the centers of curvature of the dillerent areas of said disk, that is not essential, and, of course. would not be the case if the axis 41 and 4-2 were relatively inclined.

It to be understood that the lenses above described may be surfaced by osoillating the pieces of glass of which they :l'ornled. upon laps having su' iv curved areas; such oscillations being in #hc direcas it is obvious that var-ions iuodiiicat tion of the junction of the different ptric elements of the taccs being; to and. such oscillation in: Off course, he of acted by hand, but may i: rapidly efdeci't-ed any suitable mechanism, for instance lio.

common axis of oscillates]. (W1. ch the axis {,{Ql'lOlfL'tlOll of the su formed} to the extent of the 1 zone. 36 indicated in Fig il at freedom for ome such axis ovei'ne t, to even n; extent, is ad rate; \us in forming surface of the type cunts a" in I, and. V, because it decussative movements of the pa abra..1ng material and thus avoids the mation of ruts and scratches which to ca'sioned. forcing particles of abradmaterial to reps; dilly traverse the sz'iine path. There ore, ll. do not de he to limit nrysclf to the pi cise details of construction, 4 range nent and pincediure her to JJ may be made therein WltllO'Lti? departing itial features of my invention,

a 111 the appended claims.

I claim:

'i An op ineludm 5 with a. cylindrical component.

2. An optical element having one s" V "face including spherical. area and a eerie area. 1

3. An optical element having one suit tic face including a spherical area and an area. with cyliil cal component; and haw ing adjacent edges of said areas n i a region or corn non si. An optical elem face including areas merged ir ture.

5. An optical element having one side sur- 123%;

face including a s )hcrical area and an area with a cylindrical component, and having; adjacent edges of said n and in an intermediate transition zone. 6. An or deal. element havingcne sir: face including a spherwith a cylindrical cor aoiacent edges said ing spherical and another including a cylindrical component.

9. An optical element having each side surface includin distinct areas one area.

being spherical and another including a cylindrical component; said spherical areas being opposite each other.

10. An optical element having each side surface including distinct areas, one area being spherical and another including a cylindrical component; said cylindrical components being in cross relation.

11. A multifocal ophthalmic lens .having one side surface including a spherical area and an area with a cylindricalcomponent; said areas extending respectively above and. below the 180 degree axis of said lens.

12. A niultifocal ophthalmic lens having one side surface including a spherical area and a toric area; said areas extending re spectively above and below the 180 degree axis of said lens.

.13. A multifocal ophthalmic lens having each side surface including a spherical area and a torie area; said areas extending 1n opposite directions from a medial region of said lens; said toric areas being in transverse relation to each other.

14. A multifocal ophthalmic lens having each side surface including a spherical area and a toric area; said areas extending respectively above and below the 180 degree axis of said lens; said toric areas being in cross relatiombelow said axis.

15. An ophthalmic lens having one surface which. is of different dioptric curvature at different regions respectively spherically andtorically curved; said surface being part of a surface of revolution with respect to a single axis of rotation transverse to the plane of the junction between said regions 7 -16. An ophthalmic lens having one surface which. is smoothly continuous throughout its area but of different dioptric curvature at dilferent regions; regions respectively above and below the geometrical center of thelens being respectively spheri cally and torically curved; said regions having acominon curvature at their junction; said surface being part of a surface of revo lution with respect to a single axis of rotutiontransverse to the plane of the junction between said regions.

1?. An ophthalmic lens formed of a singl piece of glass of uniform index of refraction, having one surface which is smoothl continuous throughout its area but of d1 ferent dioptric curvature'at different regions; regions respectively above and below the geometrical center of the lens being respectively spherically and torically curved; said regions having a common curvature at their i'unction; said surface being part of v 18. An ophthalmic lens having one sur-.

face which is of different dioptric curva ture at different regions respectively spherically and toricall curved; said surface being part of a sur ace of revolution-with respect to a single axis of rotation transverse to the plane of the junction between said regions; said lens having its opposite sur- (face of different dioptric curvature at differ: ent regions, respectively spherically curved and torically curved.

19. An ophthalmic lens having one surface which is of difl'erent dioptric curvature at different regions respectively spherically and torically curved; said surface being part of a surface of revolution with respect to a single axis of rotation transverse to the plane of the junction between said regions; said lens having its opposite surface of different dioptric curvature at diflerent regions, respectively spherically curved and torically curved; the toric curvatures upon opposite surfaces of said lens forming a cross cylinder.

20. An ophthalmic lens formed of a single piece of glass of uniform index of refraction, having one surface which is smoothl continuous throughout its area but of di ferent dioptric curvature at difi'erent regions; regions respectively above and below the geometrical center of the lens'being respectively spherically and torically curved; said regions having a common curvature at their junction; said surface being part of a surface of revolution with respect to a single axis of rotation normal ,to the plane of the junction between said regions; said lens having its opposite surface smoothly continuous throughout its area but of different dioprric curvature at different regions; regions respectively above and below the geometrical center ,of the lens being respectively spherically curved and torically curved; said regions having a common curvature at their junction; the toric curvatures upon opposite surfaces of said lens forming a cross cylinder.

21. A method of forming an optical element having one side surface including a spherical area and an area with a cylindrical component; which consists in relatively turning said element in cooperative relation with another element having one side surface 'includin a spherical area and an area with a cy indrical component; such turning movement being'in the direction of the junction between said areas and upon an axis of generation of said surface, common 'to both 'of said elements.

22. -A method of forming an optical element with a smoothly continuous surface, including a spherical area and an area with a cylindrical component, which consists in turning the element to be thus'surfaced in cooperative relation with another element having an oppositely counterpart surface; such turnin movement being in the direction of the unction between said areas and upon an axis of generation of said surface,

which axis is common to both of said elements.

23. An optical element having one sic'le surface including areas of respectively ,cli'fi ferent dioptric power generated from; a.

single axis of revolution and merged in a common circular curvature in a junction plane transverse to said axis of revolution; all of said surface coinciding with circular arcs concentric with said axis of revolution in all planes parallel to said junction plane;

and one of said areas including a oyliiidrical. component.

In testimony whereofll have hereunto i signed my name at Philadelphia; lz eu isyl- Q Vania, this twentieth da of October,

ART UR EAl'GlB-L Witnesses FRANK E. PAIGE; CAROLYN E. REUTER. 

